<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Number和Math</title>
</head>

<body>

    <script>
        let a = 10
        console.log('判断一个数是不是整数：' + Number.isInteger(a));

        let b = 1.123456
        console.log(b.toFixed(3));
    </script>
</body>

</html>